The article by Phillips and Danner1 in the April 10, 1995, issue of the ARCHIVES made no mention of alcohol intake in the individuals surveyed. As they examined the relationship between cigarette smoking and sleep disturbance, they controlled for possible confounding factors, ie, caffeine intake and depression. They showed, with a multiple regression analysis, that "for problems staying asleep and daytime sleepiness, smoking status was still significantly related, whereas for problems going to sleep, smoking was no longer a significant predictor."1
Cigarette smoking is significantly related to alcohol intake in the general population.2 Furthermore, alcohol intake is related to problems staying asleep3 and daytime sleepiness.4 Thus, the relationship between cigarette smoking and sleep disturbance reported by phillips and Danner1 could be attributable to alcohol intake.